Hitherto, printed circuit boards have been widely used in the field of electric appliances. In printed circuit boards, holes for inserting leads of electronic parts with leads are small in diameter in order that solder may not come out to the upper side through insertion holes when soldering by flow method. Therefore, when inserting an electronic part with leads, for the ease of insertion of leads, it has been widely known to fix a separately fabricated insertion guide preliminarily to the printed circuit board.
The insertion guide of a prior art is described below by referring to FIG. 20 and FIG. 21. An insertion guide 101 has fixing protrusions 102 near the central part, and these fixing protrusions 102 are fitted into positioning holes 104 provided in a printed circuit board 103, and it is mounted on the printed circuit board 103. When the insertion guide 101 is thus mounted on the printed circuit board 103, conical guide holes 107 for guiding leads 106 of an electronic part 105 provided at both ends of the insertion guide 101, and penetration holes 108 of small inside diameter are positioned so as to be coaxial with insertion holes 109 of the printed circuit board 103. In this state, when the leads 106 are inserted into conical guide holes 107, the leads 106 can be easily inserted along the conical portion of the guide holes 107.
In the constitution of the prior art, first, regarding the insertion guide, unless the electronic part with leads is fixed provisionally by clinching the lead wires, the electronic part with leads may drop off while conveying the printed circuit board. Next, regarding the printed circuit board, unless the part is fixed provisionally by using adhesive or clinching the leads, the part may drop off while conveying the printed circuit board.